ToF Sensor State Control to Prevent Light Sensor IR Interference
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Solution Overview
Problem
The accuracy of data measured by light sensors in electronic devices is affected when a Time of Flight (ToF) sensor is turned on due to the reflection of its infrared light pulses, leading to unintentional triggering of device functions.
Innovation Solution
A processor controls the ambient light sensor and proximity sensor to be turned off when the ToF sensor is on, and vice versa, using GPIO pins or driver commands to manage their states based on the ToF sensor's enablement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the ToF sensor is turned on to obtain depth information, then 3D imaging capability is improved, but accuracy of light sensor measurements deteriorates due to infrared light pulse interference
Solution Approach 1:
The processor controls the light sensor to be turned off before the ToF sensor is activated, preventing the light sensor from measuring during the period when infrared light pulses are emitted. This preliminary action eliminates the interference problem before it occurs.
Solution Approach 2:
The system dynamically adjusts the working states of different sensors based on the current functional requirements. When 3D imaging is needed, the ToF sensor is activated and the light sensor is deactivated; when ambient light detection is needed, the light sensor is activated and the ToF sensor is deactivated. This dynamic state management resolves the contradiction between the two sensor functions.
2Productivity
If the light sensor operates simultaneously with the ToF sensor, then sensor utilization efficiency is improved, but data accuracy deteriorates due to infrared light interference
Solution Approach 1:
The system implements periodic switching between different sensor modes based on the current application requirements. The processor alternates between activating the ToF sensor for 3D imaging functions and activating the light sensor for ambient light detection, ensuring that only one sensor is active at a time to prevent interference while maintaining high overall utilization efficiency.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach prevents inaccurate data measurement by light sensors, thereby avoiding unintended device functions and enhancing user experience.
Implementation Method 1
A time of flight (ToF) sensor can obtain the depth information with high efficiency and high quality... a distance from the object is calculated by detecting a round trip time of flight of the infrared light pulse
Implementation Method 2
An infrared light pulse (for example, a light pulse with a wavelength of 940 nm) is continuously sent to an object
Implementation Method 3
an infrared light pulse emitted by the ToF sensor hits both the ToF sensor and the light sensor of the electronic device after being reflected by an object
Data Source
AI summary
An electronic device includes a time of flight (ToF) sensor, a proximity sensor, and an ambient light sensor. The ToF sensor, the proximity sensor, and the ambient light sensor are located on a same side of the electronic device. When the ToF sensor is turned on, a light sensor (for example, the proximity sensor and/or the ambient light sensor) may be controlled to be turned off, and when the ToF sensor is turned off, the light sensor may be controlled to be turned on. Alternatively, when the ToF sensor is turned on, data measured by a light sensor is discarded, and when the ToF sensor is turned off, a corresponding function is implemented based on data measured by the light sensor.